Ignition control



.Aug. 28, 1945. s. ,M. UDALE IGNITION CONTROL Filed Jan. 22, 1945 2Sheets-Sheet 1 QUBQQ I N NW INVENTOR.

S. M. UDALE Aug.. 28, 1945.

IGNITION c Filed Jan. 22, 1945 2 Sheets-Sheet 2 Patented Aug. 28, 1945George M. Holley and Earl Holley Application January 22, 1945, SerialNo. 574,012

'1 Claims. (01. 123 1 17) The object of this invention is to advance thespark at part load to retard the spark at idle and to partially retardthe spark at high manifold air pressures.

Figure 1 shows the invention applied to the ignition control of anordinary supercharged engine used at sea level and up to 10,000 feet.

Figure 2 shows a modification to adapt the device-for engines used ataltitudes in excess of 10,000 feet. 1

Figure 3 shows an alternative construction for application to a variableVenturicarburetor.

' In Figure 1, air enters at [6 and flows through the Venturi H to thesuperchargerl2 past the throttle l3. A port I4 is located adjacent toand on the atmospheric side of the upstream lip of the throttle l3 whenclosed to the idling. position. The opening I5 is located adjacent toand .on the engine side of the downstreamlip of the throttle l3.whenclosed to the idling position. The diaphragm'l6 is responsiveto thepressure differences at the ports 14 and I5 and controls a :06. 32.

I1 is a connection on the pressure side of the supercharger 12. Thispressure istransmitted through a pipe l8 to a chamber I9 where a piston26 reciprocates. A spring 22 engages with the piston 26 and a spring -2lengages with themaphragm l6 and thus opposes the spring 22 through therod 32. An adjustment 23 regulates the springs 2| and 22. A stop 24limits the idling position of the rod 32, which rod is connected to acircuit breaker 25. When the device is used on an airplane, a connectionI! leads to a chamber 26 (Figure 2), in which is located a barometricelement 28, controlling a valve 29 so that the pressure in the pipe I8is less than the supercharger the diaphragm 49. When the throttles 34-35assume the idling position, valve 4| rises and permits the passage 43 tocommunicate with thepassage 50, which communicates with the chamber5|.below the diaphragm 49.

Passage 52 communicates with the air entrance 33'and through arestriction 53 with the passage 41. Passage 52 communicates through arestriction 54 with the passage 50. An adjustment 55 regulates thesprings 56 and 51." Stop 58,1imits the upward travel of the diaphragm49. An eccentric 59, controlled by a lever 60, limits the downwardtravel of the diaphragm 49.v Fuel enters at 6| and flows into a chamber62, controlled by two valves63-64. These valves are controlled by thediaphragms 6566. The pressure acting on the diaphragms 65-66 is thepressure existing in the air entrance 33, which is admitted through Ithe passage 61. Passage 68 connects the two air chambers 69 and 10together. Fuel passage H is controlled by the movable needle 12, whichis moved by the lever '13 and the push rod 14.

Operation of Figzmes 1 and 2 At idle, the spark is retarded, say to 4 at550 revolutions per minute. At maximum advance, the advance is to 45(part throttle cruise), and at wide open throttle, the advance varies,say from 30 at 40 Hg to 35 at 35" Hg. Thesefigures vary with eachengine, but the higher the pressure, the lower the spark advance.

At altitude (25,000 feet) the, spark retard under the influence of 30"Hg, manifold air pressure will be too great with Figure 1 because thepiston will be acted upon by a 15" Hg pressure difference. With theconstruction shown in Figure pressure in H. The pressure in the pipe l8escapes through an opening in the piston 20. The stop 3| limits theadvance (the maximum possible under cruising conditions) of the ignitionsystem. At idle, the maximum retard is determined by the stop 24. Theadjustment 23 takes care of the intermediate spark position duringvariable load.

In Figure 3, 33 is the air-entrance, 34 and 35 are the variable Venturithrottles geared together by the gears 36 and 31. 38 is a fuel passagedischarging between two Venturi throttles 3435. The lever 39 carries anadjustable stop 40, which engages with a valve 4|, which is held on itsseat by the spring 42. Passage 43 communicates with the chamber 44 tothe right of the throttle 34 and communicates through a passage 45 withthe throat of the variable Venturi. which contains the spring 42,communicates with the passage 41 and with the chamber 49 above Chamber46,

2, the Hg pressure will expand .the element 28 and the valve 29 willrestrict the flow of compressed air. At sea level, the two devicesshould be adjusted to give the same advance for the same manifold airpressure. At altitude, it is desirable that the same absolute value ofsupercharger pressure controls the advance to give the same advance asthat found desirable at sea level with the same pressure.

Operation of Figure 3 As the throttle is closed towards the idlingposition, the adjustable stop 40 engages with the valve 4!, which risesand cuts off the connection between chamber 44 and chamber 48 so thatthe pressure in the chamber 48 becomes atmospheric because of theopening 53. Simultaneously, suction is applied to the chamber 5| throughthe pipe 59. Therefore, the diaphragm 49 is drawn down and the spark isretarded. The limit of the retardation due to the idle suction isregulated by the lever 60 and the cam 59, which acts as a stop. As thethrottle opened to the position shown in the drawing, the valve 4! isseated by the compression spring 42, and in the position shown, suctionfrom the Venturi passage 45 is transmitted through the passage 43 to thechamber 48, which is located above the diaphragm 49. Diaphragm 49 isthus drawn upwardly and the rod 32 is drawn upward, advancing the sparkas far as possible. The limit to the advance of the spark on the partload is determined by the stop 58. When the throttle approaches wideopen, the spark assumes an intermediate position, determined by the twosprings 56 and 51. This position is determined by the adjustment 55.

What I claim is: r?

1. In a spark control device for an engine having a circuit breaker,comprising an air entrance leading to the engine, a throttle valvetherein, a first port in the air entrancelocated on the atmospheric sideof the throttle when the throttle is closed to the idlingipositio'n, .asecond port located on the engine side of the throttle when the throttleis closed to the idling position, a diaphragm. responsive to thepressuredifierences between the two ports, said diaphragm beingmechanically connected to said circuit breaker, means whereby when thethrottle is opened, the first port is placed on the engine side of thethrottle and the second port is placed on the atmospheric side of saidthrottle, two stops, one for limiting the spark advance when thethrottle is opened and the other for limiting'the retard when thethrottleis closed to the idling position, two yieldable opposed meansfor moving the diaphragm in each direction and for holding. thediaphragm in an intermediate position when the throttle is openedtowards the wide open position.v '3 1" 2. A device as set forth in claim1' in which there is a supercharger connected to the air entrance, achamber, a passage connecting the supercharger and said chamber, amoving wall in said chamber, said moving wall being mechanicallyconnected to said circuit breaker as to move the circuit breaker towardsits retarded position on an increase in supercharger pressure.

3. A device as set forth in claim 1 in which there is a superchargerconnected to the air entrance, a chamber, a passage connecting thesupercharger to the chamber, a second chamber, a moving wall therein, apassage connecting the two chambers, a valve in said passage, abarometric element in said first chamber connected to said valve, saidmoving wall being mechanically connected to said circuit breaker so asto move the circuit breaker towards its retarded position on an increasein supercharger pressure and on a decrease in altitude.

4. In a spark control device for an engine having a circuit breakercomprising an air entrance, a throttle valve therein, an air chamber, adiaphragm therein dividing said chamber into two parts, a passageconnecting the first part with the suction on the engine side of saidthrottle, a passage connecting the second part with the pressureexisting in the air entrance, valve means interconnected with saidthrottle for reversing these connections when the throttleis initsidling position, two yieldable means engaging with said diaphragm soas to oppose its movement in either direction and for opposing theengine suction, a connection from the diaphragm to the circuit breaker.

5. A device as set forth in claim 4 in which there are two adjustablestops limiting the travel of the diaphragm in each direction.

6. A ,device as set forth in claim 4 in which there is an adjustment foradjusting the springs opposing the movement of said diaphragm in eitherdirection in response to said engine suction.

'7. In a spark control device for an engine having a variable Venturithrottled carburetor comprising an air chamber, a diaphragm thereindividing said chamber into two parts, a passage connecting the firstpart to the suction existing in said venturi, valve means'operated bysaid throttle adapted to second part of the chamber ,to suction existingin the venturi so as toreverse said connection when the.throttle is inidling position, two yieldable means for opposing the movements of saiddiaphragm, a connection from said diaphragm to said spark controldevice.

STANLEY M. UDALE,

